1. Field of the Invention
The present invention relates to thermal management of an electronic system, and more specifically to monitoring and analyzing airflow parameters in a computer system.
2. Background of the Related Art
Advances in the power and performance of electronic systems have led to an increasing emphasis on thermal management and power management. In air-cooled electronic devices, it is useful to know the real-time thermal and cooling performance in terms of various airflow parameters. In computer systems, and particularly in servers, mechanisms have been added to monitor parameters such as temperature and fan speed at various locations. However, knowledge of fan speed and temperature provides a very limited understanding of the thermal and cooling performance of a server system. For example, fan speed does not even provide a reliable indication of airflow rate, because factors such as internal air paths, external blockages, and back pressure can affect the actual airflow rate independently of fan speed.
Instrumentation other than fan speed and temperature sensors has certain disadvantages. For example, airflow measurement subsystems incorporating pitot tubes can provide an accurate indication of airflow rate, but such subsystems are expensive relative to the overall cost of a computer system. Other devices used as airflow meters, can create excessive backpressure that reduces the cooling efficiency of the computer system. Such considerations have generally kept direct airflow measurement from being adopted in server systems.